U.S. Geological Survey Open-File Report 2004-1227
By G.R. Buell, H.W. Markewich, R. Kulisek, S. Pollard, and T.T. Cook
The S3C database is a pedon-based, site-specific,
soil-organic-carbon (SOC) database for mineral soils of the
The S3C database includes both pedon-level and horizon-level data with values for organic carbon, carbonate, bulk density, particle size (total sand, silt, and clay), texture class, pH, water content, and soil volume (particles <2 mm diameter). SOC mass storage (kg m-2) was calculated for each soil horizon and, at the pedon level, for the following standard depth intervals—0 to10, 0 to 20, 0 to 50, 0 to 100, 10 to 20, 20 to 50, and 50 to 100 centimeters. Mass-weighted mean values for carbonate, bulk density, particle size and texture class, pH, water content, and soil volume were also calculated for the standard intervals.
The horizon-level data are provided for those interested in the study of site-specific carbon-cycling processes. The pedon-level data are provided for those interested in regional analysis and modelling.
The S3C database was compiled from the following
(1) U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil Characterization Database (U.S. Department of Agriculture, 2001—7,821 pedons, 1938 to 1995, geographic coverage—basinwide);
(2) two surveys of high-elevation soils in the Southern Blue Ridge (Fenneman, 1938) physiographic province (Daniels and others, 1987a, b—8 pedons, Graham County, North Carolina; Feldman, 1989, 2000, Feldman and others, 1991a, b—37 pedons, Swain and Yancey Counties, North Carolina, Sevier County, Tennessee, Grayson and Smyth Counties, Virginia);
(3) University of Arkansas, Soil Characterization Database (University of Arkansas, 2000—495 pedons, 1955 to 1992, Arkansas statewide);
(4) University of Illinois, Soil Characterization Database (University of Illinois, 2001—778 pedons, 1928 to 1990, Illinois statewide); and
(5) a survey of flood-plain and delta soils in the Mississippi Alluvial Plain (Fenneman, 1938) physiographic province (Schumacher and others, 1988—76 pedons, Louisiana statewide).
The data sources, methods, and formulas used to estimate SOC storage and inventory for these soils are discussed in Buell and Markewich (in press). The S3C database will be updated as significant “blocks” of new data are received, checked for accuracy, standardized, and merged. The database is downloadable through the links on this page. Three data files (pedon01, horiz01, and taxon01) are provided in Microsoft Access 2000 and tab-delimited ASCII formats (compressed in ZIP or TGZ volumes below). The database dictionaries are provided in Microsoft Excel 2000 (pedvar.xls, hznvar.xls, and taxvar.xls) and HTML (pedvar.htm, hznvar.htm, and taxvar.htm) formats. The database dictionaries are also included in the field definition column of each Access data table (pedon01, horiz01, and taxon01). The footnote references for the field definitions are included in the Access version of the database as separate tables (pedon01-footnotes, horiz01-footnotes, and taxon01-footnotes).
The pedon file (pedon01) contains site-level data such as soil series name and geographic location as well as SOC storage and related ancillary data for standard depth intervals; the horizon file (horiz01) contains the physical and chemical characterization data for individual soil horizons; and the soil-taxonomy file (taxon01) contains the descriptive data for all of the soil series presently described by the U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil Survey Center, Lincoln, Nebraska. The entire soil-series database was included in the taxonomy file to facilitate updates to the pedon and horizon files. As the pedon and horizon files are updated, data for previously unrepresented soil series will likely be added. It is the authors’ intent that these data will be helpful to those involved in ecological studies, environmental assessments, and landuse planning efforts that require the use of SOC data.
 The pedon is the smallest physical sampling unit of a soil (generally from 1 to 10 square meters in area and as deep as the soil is formed) required to describe the variability in the properties of that soil at a specific location (Soil Survey Staff, 1999). Pedons generally are sampled by horizon rather than by arbitrary depth increments because soil horizonization provides a physical model for the physical and chemical development of the soil.
Buell, G.R. and Markewich, H.W.,
in press, Data compilation, synthesis, and calculations used for organic-carbon
storage and inventory estimates for mineral soils of the Mississippi River
basin, chap. A of Markewich, H.M., ed., Soil-carbon storage and
inventory for the continental
Daniels, W.L., Everett, C.J., and Zelazny, L.W., 1987a, Virgin hardwood forest soils of the southern Appalachian Mountains: I. Soil morphology and geomorphology: Soil Science Society of America Journal, v. 51, p. 722-729.
Feldman, S.B. 1989, Taxonomy, genesis, and parent
material distribution of high elevation forest soils in the southern
Appalachians: unpublished M.S. thesis, Virginia Polytechnic Institute and
Feldman, S.B., 2000, unpublished data, provided to USGS in 2000.
Feldman, S.B., Zelazny, L.W., and Baker, J.C.,
1991a, High-elevation forest soils of the southern
Feldman, S.B., Zelazny, L.W., and Baker, J.C.,
1991b, High-elevation forest soils of the southern
Fenneman, 1938, Physiography of eastern
Schumacher, B.A., Day, W.J., Amacher, M.C., and
Miller, B.J., 1988, Soils of the Mississippi River alluvial plain in
Soil Survey Staff, 1999, Soil taxonomy, a basic system of soil classification for making and interpreting soil surveys, 2nd ed.: U.S. Department of Agriculture, Natural Resources Conservation Service, Agriculture Handbook Number 436, 870 p.
Staff, 2003, Official soil series descriptions:
U.S Department of Agriculture, Natural Resources Conservation Service,
Sundquist, E.T., Stallard, R.F., Bliss, N.B.,
Markewich, H.M., Harden, J.W., Pavich, M.J., and Dean, Jr., W.E., 1998,
U.S. Department of Agriculture, Natural Resources Conservation Service, 2001, National Soil Characterization Database, accessed September 1, 2001, at URL http://ssldata.nrcs.usda.gov/.
University of Arkansas, 2000, unpublished data, Soil Characterization Laboratory, Fayetteville, AR, provided to USGS, 1999-2000.
ASCII format: WINDOWS zip file (s3c_ascii.zip)
UNIX gzip tar file (s3c_ascii.tar.gz)
MS Access format: WINDOWS zip file (s3c_access.zip)
MS Excel format: WINDOWS zip file (s3c_fielddef_excel.zip)
HTML format: WINDOWS zip file (s3c_fielddef_html.zip)
UNIX gzip tar file (s3c_fielddef_html.tar.gz)
Gary R. Buell (corresponding author), firstname.lastname@example.org, tel: 770-903-9160, fax: 770-903-9199
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